Field of the Invention
The present invention is directed in general to voltage converter and methods for operating same. In one aspect, the present invention relates to the manufacture and use of synchronous rectifier voltage converter circuits.
Description of the Related Art
DC/DC power converter circuits or devices are important in many portable battery-operated electronic devices, such as cellular phones and laptop computers, which are supplied with power from batteries. Typically, a DC/DC circuit converts DC power from one voltage to another voltage by accepting a DC input voltage and producing therefrom a DC output voltage which may have a different voltage level than the DC input voltage. For instance, a DC-to-DC converter may use a charging inductor and load capacitor to convert a relatively high input battery voltage to a lower or negative DC output voltage. In cases where the amount of energy required by the output load is small enough to be transferred in a time that is shorter than the whole commutation period, discontinuous mode DC-DC converters are provided where the current through the charging inductor falls to zero and remains at zero during part of the period so that the inductor is completely discharged at the end of the commutation cycle. Because of accuracy limitations in controlling the discharge of the inductor, discontinuous mode DC-DC converters are susceptible to reverse current events if the inductor discharging is stopped too late, causing reverse electrical current to flow to a ground terminal from an output terminal connecting to a load circuit through the inductor. When a reverse current occurs, power conversion efficiency of the DC-DC converter in particular is impaired. And while solutions have been proposed for improving switching control of discontinuous mode DC/DC converters, they typically require large circuits which consume excessive power.
Accordingly, a need exists for improved DC/DC converter devices and associated methods of operation to overcome the problems in the art, such as outlined above. Further limitations and disadvantages of conventional processes and technologies will become apparent to one of skill in the art after reviewing the remainder of the present application with reference to the drawings and detailed description which follow.